在 node.js 中的两个 javascript 文件之间发送和接收事件

Question

I am trying to communicate between two javascript files using EventEmitter, but I am struggling to get it working in both directions.

I have server.js:

let api = require('./api')

// Does not work
api.on("yo", data => {
    console.log(data)
})

// Works
api.emit("ready", "Server ready") 

and api.js:

const EventEmitter = require('events')
let api = new EventEmitter()

// Works
api.on("ready", data => {
    console.log(data)
})

// Does not work
api.emit("yo", "yo yo")

module.exports = api

server.js is able to emit events to api.js , but not the other way around. I have tried module.exports and requiring both files in each other respectively at the same time, but that is causing errors.

How can I accomplish two-way emits/ons between these two files?

Answer 1

At first api.js is initialized and at that moment nobody is subscribed on 'yo' event yet. So you shouldn't emit any events during any module initialization at all. Try to emit events afterwards somehow.

OR you can move all subscribing stuff into another module in which you can emit any event after all subscriptions are done.